The K-206 series comprises compact metal-clad medium-voltage cubicles for receiving, distributing, and switching three-phase AC at 50/60 Hz in 6(10) kV networks with either an isolated neutral or a neutral grounded via an arc-suppression coil (Petersen coil) or active resistor. Compartmentalization with a draw-out breaker localizes fault effects and enables safe access for maintenance.

A key advantage is the cabinet depth of only 1000 mm, making K-206 suitable for narrow MV rooms and brownfield upgrades without building rework. The panels are engineered as retrofit replacements for legacy KSO cells while preserving interface dimensions and cable routing, minimizing downtime at operating sites.

Typical applications span all power-plant types, factory-built modular e-houses, utility distribution substations, industrial and oil & gas facilities, as well as expansions and refurbishments of existing switchgear without increasing footprint.

The frame is made of high-strength galvanized steel with precise cold-formed geometry; assemblies are joined by reinforced blind rivets and threaded fasteners. Exterior parts-front doors and side panels of end cubicles-are finished with RAL 7035 powder coating for long-term corrosion resistance.

Inside, independent relay/control, withdrawable unit, busbar, and cable compartments are separated by solid barriers to prevent fault propagation. Epoxy bushing insulators are used for fixed contacts and bus sectionalizing to meet insulation requirements and facilitate service.

Standards compliance.

• IEC 62271-200 - metal-enclosed switchgear; internal arc classification IAC (project-specific);
• IEC 62271-100 - 12 kV vacuum circuit-breakers;
• IEC 62271-102 - earthing switches;
• IEC 60071-1 - insulation coordination (standard level);
• EN/IEC 60721-3-3 - environmental conditions for stationary, weather-protected indoor locations;
• EN/IEC 60529 - degree of protection, IP.

Scope of use

K-206 is intended for new and refurbished indoor installations:

• retrofit of legacy KSO cells without altering civil works or cable routes;
• auxiliary medium-voltage switchgear of TPP/CCGT/engine-based plants (incoming, bus-section, feeders);
• main/central distribution substations at industrial sites: metallurgy, chemicals, pulp & paper, agriculture;
• package substations and urban 6-10 kV networks, redundancy and metering nodes;
• oil & gas: well pads, pumping stations, booster/transfer stations, gathering and processing facilities.

Service conditions

• Environmental classification - EN/IEC 60721-3-3 (higher severity classes on request);
• Ambient temperature -25…+40 °C; for lower temperatures - room heating for the MV lineup;
• Altitude up to 1000 m (above that - verify insulation/cooling by calculation);
• Non-hazardous indoor atmosphere, free of conductive dust (typical industrial environment per EN/IEC 60721-3-3);
• Enclosure degree of protection - IP31; maintenance - single-sided.

Design features of K-206

• Compact 1000 mm depth - ideal for constrained rooms and retrofit projects;
• Four-compartment layout: relay/control ⋅ withdrawable unit ⋅ busbar ⋅ cable;
• Epoxy bushing insulators - bus sectionalizing and overvoltage robustness;
• Shutter mechanism covers primary contacts when the breaker is in the test position;
• Mechanical/electromagnetic interlocks - prevention of incorrect operations;
• Shielded secondary wiring ducts with single-point grounding - improved EMC immunity.

Configuration and options

• 12 kV vacuum circuit-breaker (manufacturer per project), CTs/VTs, ZnO surge arresters;
• Functions: incoming, bus-section, feeders, metering/measuring, VT panel;
• Top/bottom cable entry; ready for KSO retrofit with matched interfaces;
• Protection IEDs with AR/ATS/UFLS, IEC 61850 (MMS/GOOSE) and telecontrol;
• Options: motor operators for CB/earthing switch, arc-flash sensors, relay-compartment heaters.

Reliability and service life

• Fault effects confined within the affected compartment - the lineup remains operable;
• Vacuum breakers class M2/E2/C2 - endurance up to 30,000 O-C cycles;
• Galvanized-steel body, RAL 7035 powder coat - durable corrosion protection;
• Structured secondary wiring - faster service and diagnostics.

Technical data

We offer documentation for manufacturing K-206 switchgear:

Tender package. Single-line diagrams, inquiry sheets, and technical description for procurement and feasibility checks.

Working drawings and 3-D models. Layout/assembly, BOM, secondary schematics, and cable schedules - tailored to your production.

Contract manufacturing of assemblies. We arrange enclosure and mechanism production with partners; you handle assembly, installation, and routine factory tests.

Adaptation and retrofit. We design drop-in replacement cubicles to mate with existing busbars and secondary circuits without changing the building works.

Why work with us:

No staff expansion. Documentation is structured for engineers of average qualification.

Fast series launch. Standardized assemblies and repeatable solutions shorten schedules and reduce risks.

Technical support. We support manufacturing, assembly, commissioning, and integration of protection/SCADA.

Need details on K-206? Email: inbox@proekt-energo.com

A correction made at the design stage costs far less than during production - and orders of magnitude less in operation.

PDF - Download K-206 Technical Information